1. Field of the Invention
The present invention relates to an apparatus for carrying out writing or reading two-dimensional scanning patterns. More particularly, the present invention is directed to such two-dimensional scanning apparatus which enables the obtaining of a distortionless light beam scan image on a surface of a medium to be scanned.
2. Description of the Prior Art
Two-dimensional scanning apparatus of the type mentioned above is known in the art and widely used in various apparatus such as laser printer apparatus and facsimile image transmission apparatus. In the laser printer apparatus, a laser beam is modulated by image information including figure or character coming from an electronic computer or facsimile image transmitter, the modulated beam is two-dimensionally deflected and high quality hard copies are produced at a high speed employing an electrophotographic method or heat mode recording method. In the latter mentioned facsimile image transmission apparatus, the non-modulated laser beam is two-dimensionally deflected to make the beam incident upon a two-dimensional pattern and the reflected light from the pattern is photo-electrically converted to obtain two-dimensional image information.
With the two-dimensional scanning apparatus according to the prior art, scanning effected on a scanned surface contains some distortion. Therefore, it is required to correct the distorted information. For example, a position detector, a large capacity memory or a correcting operation circuit has been used to electrically correct the distorted information. However, such electrical signal processing means is complicated in structure and generally brings forth various disadvantages.